Oxidation of triplet C60 by hydrogen-bonded chloranil: Efficient formation, spectrum and charge-shift reactions of C60+• cation radical

László Biczók, Henry Linschitz

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Abstract

The rate of oxidative quenching of 3C60 by chloranil (CA) in CH2Cl2 is much enhanced by added trifluoroacetic acid (TFA) or hexafluoro-2-propanol (HFIPA). These additives have similar hydrogen-bonding powers but differ widely in their proton acidities. In both cases, quenching rate constants calculated for H-bonded CA increase sharply with additive concentration. H-bonded clusters around the quinone are postulated in which electron transfer is coupled to fast protonation of CA-• by TFA, and strong H-bonding or solvation of charged radicals by HFIPA. This is consistent with observed neutral semiquinone formation, higher radical yields, and much slower back reactions for TFA. The C60+• spectrum (ε = 25 000 ± 2000 M-1 s-1 at 980 nm) shows low absorption throughout the visible region. Charge-shift reactions of C60+• and arenes follow Rehm-Weller-Marcus kinetics and afford efficient preparation of arene+• cation radicals using visible light.

Original languageEnglish
Pages (from-to)11051-11056
Number of pages6
JournalJournal of Physical Chemistry A
Volume105
Issue number49
Publication statusPublished - Dec 13 2001

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ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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